z^ 



Journal of Agriculture. 



[ii Jan., 1909. 



Grasses. 

 Various plots have been sown to test the relative values of grasses and 

 other fodder plants. A number of those tried have partially succumbed to 

 the dry weather. The most promising of these unsatisfactory grasses will 

 be tried under irrigation, and the re.st discarded. Good growth has been 

 made bv Lolium pcrenne (English rye), Lolium lialicum (Italian rye), 

 " Phalaris Commutata " (Toowoomba canaiy grass), and Bromns unioloides 

 (Prairie grass). The latter seems to be a better winter grass for our district 

 than the much-bcK^med " Phalaris commutata."" 



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STUDENTS CROSS-FERTILISING WHEAT. 



NITROGEN AND NITRAGIN. 



Alfred J. Ewart, D.Sc., Ph.D., F.L.S., Government Botanist and 



Professor of Botany at the Melbourne University. 



The chemical element nitrogen takes an essential part in the compo- 

 sition of all plants and is especially abundant in buds, seeds, flowers, 

 growing tips, and. in fact, in all parts rich in the living plant substance, 

 protoplasm. Hence a steady supplv of nitrogen must be obtained in the 

 food of plants, although in this respect the plant is far less wasteful than 

 the animal and may use the same nitrogen over and over again once it 

 has been absorbed. The source of the plant's supply of nitrogen is 

 .almost solely from the nitrates of calcium, magnesium, potassium, and 

 •sodium which are continually being produced in the presence of the requi- 

 site bases in every fertile soil during the decom]X)sition of its nitrogenous 

 "humus. The nitrogen of this humus is oxidized in the presence of free 

 oxvgen bv nitrifying bacteria, which are present in all ordinary soils. 

 Ultimately nitric acid is formed, usually with ammonia and nitrous acid as 

 intermediate products, and this nitric acid combines with the alkaline bases 

 present in the soil to form nitrates. 



This process is a continuous one, and takes place most rapidly when the 

 soil is warm, moderately moist and well aerated. It stops, or becomes 

 very slow, if the soil is at all acid, completely dry, very cold or in a 

 swami)y, badly aerated condition owing to an excess of water. 



